Add ftplugin/keymap overrides, gitignore.

Add:
	.gitignore
		-add gnome-terminal/, which contains files that are automatically
		written.

	vim/ftplugin/
		-add keymap overrides to filetypes that use common operators ({, (, ',
		etc.) differently than is the norm.

	vim/ftplugin/(tex, plaintex, gitcommit, text).vim
		-set English dictionary spell-checking.

	vimrc
		-highlight incorrectly spelled words bold red.
		-prepend silent! to calls that load pathogen and the colorscheme, to
		suppress persistent error messages on remote machines that don't have
		the necessary files.

	zshrc
		-add more git aliases, and various flags to gcc
		-add gpub() function, which pushes a local git branch to the remote.